E
Statement 1This tells us that C must be exactly in the middle of A and B, so AC = 9 and CB = 9. At first glance, this seems like sufficient, but it still doesn't tell us exactly where D is. We know that CD is 8. But D could be to the left of C making BD=17 or it could be to the right, making BD=1.
Statement 2The key here is to NOT bring in the information from Statement 1. If all we know is the directionaly location of D compared to A, this doesn't give us enough concrete information to know the distance of BD. A could be any distance to the left of A, AND we are n't certain of the order of AB. it could still be BA =18...we just don't know.
TogetherIf we have A..................B (notice 18 dots) or even B..................A
From #1 we know that C must be equal distance between A & B
So, A.........C.........B
and from #2 we know that A is to the left of D, and CD = 8. Well, what about D's relation to C? D could be on the left of C or right of C and still be to the right of A (provided A is actually left of B).
If D is to the left of C and right of A, what length does that make BD? it sould make it DC +CB or 8 + 9 = 17.
What if D is to the right of C (which will still be right of A), then that makes BD = CB - CD or BD = 9 - 8 = 1
Together both statements are insufficient.
Answer E.
Rice wrote:
The points A, B, C, and D are on the number line, not necessarily in that order. If the distance A and B is 18 and the distance between C and D is 8, what is the distance between B and D?
1) the distance between C and A is the same as the distance between C and B
2) A is to the left of D on the number line
_________________
------------------------------------
J Allen Morris
**I'm pretty sure I'm right, but then again, I'm just a guy with his head up his a$$.
GMAT Club Premium Membership - big benefits and savings